Sicyonia parajaponica Crosnier, 2003

Chakraborty, Rekha Devi, Gayathri, A. P., Sreelakshmy, S., Aghana, M. & Kuberan, G., 2021, DNA barcoding of deep-sea shrimp Sicyonia parajaponica Crosnier, 2003 (Crustacea: Decapoda: Sicyoniidae) from southwest coast of India, Zootaxa 4985 (1), pp. 125-130 : 126-129

Sicyonia parajaponica Crosnier, 2003

( Fig. 1 A–H )

Sicyonia parajaponica n. sp. (Figs 10–12; 106E, F) Sicyonia japonica —Yu & Chan 1986, p. 56, 3 figs n.n. (coul.).—Liu & Zhong 1988: 249, fig. 150 (1–6).—Crosnier 1995, p. 193; Sicyonia parajaponica — Crosnier, 2003, p. 226, fig. 10 A–C, 11, 12 A–C & 106 E–F; De Grave & Fransen, 2011, p. 12, fig. 2 a–b; Radhakrishnan et al., 2012, p. 56; Shanis et al., 2013, p. 131, fig. 1, 2 A – & B, 3 A, fig. 3 A–B; Chakraborty, 2017, p. 156; Thiruvengadam, 2017, p.84, fig.1

Material examined. Sakthikulangara (off Kollam 8°56’60.78”N; 76°32’34.27”E) fish landing center, 1male (TL: 80 mm; CL: 29 mm, RL: 7 mm, Weight: 9.102 gm), 1 female (TL: 65 mm; CL: 21 mm, RL: 7 mm, Weight: 4.446 gm), 200–230 m depth during November 2019.

Characters of specimen from off Kerala. S. parajaponica is characterized by the presence of distinctive large red spot encircled by a white band on the posterior dorsum of the carapace stretching across three posterior dorsal teeth. Rostrum not overreaching scaphocerite with its tip bidentate, one tooth present on the ventral side of the rostrum and the hepatic spine is strong and well developed ( Fig. 1C ). A blunt spine like out-growth is present behind the hepatic spine. The dorsal carina of the carapace bears 5–8 teeth with posterior 4 or 5 teeth large and strong ( Fig. 1D ). Infraorbital lobe is rounded or slightly biangular. The scaphocerite is triangular and with the disto-lateral tooth overreaching the lamella. The third maxillipeds are strong and reach beyond the tip of the scaphocerite. The dorsal tooth of first abdominal segment well developed, tip pointing upwards. The tooth of the second abdominal pleura well developed, strong and acute ( Fig. 1E ). The anterior three abdominal pleura, are usually with single spine on the postero-ventral margin, whereas the fourth has three spines and fifth with two spines ( Fig. 1F ). Process of distal ventolateral lobes of petasma enlarged. The distal ventrolateral lobes of petasma are stretched transversely ( Fig. 1G ) in males while in females the rear part of thelycum considerably enlarged ( Fig. 1H ) in S. parajaponica .

Coloration: Body is reddish orange with brownish irregular marks unevenly distributed all over the body and the presence of a distinctive large red spot encircled by a white band on the posterior dorsum of the carapace.

Distribution: Taiwan, the sea of Southern China, the Philippines, the northwestern coast of Australia, the Andaman Sea and the Gulf of Aden at a depth of 10– 200 m. In India it was recorded in the inshore waters off Chennai (40–60 m depth), Thoothukudi (310 m) along the Bay of Bengal, and off Sakthikulangra. The present specimen was obtained from the deepsea commercial trawlers operated off Kollam, Arabian Sea at a depth of 200 and 230 m.

Remarks: Morphologically the specimen agrees with the original description ( Crosnier, 2003). Sicyonia parajaponica is closely similar to Sicyonia japonica Balss, 1914 in its colour pattern and morphometric characteristics. The major distinctive character to differentiate between S. parajaponic a and S. japoni ca is the large spot stretching across three posterior dorsal teeth on carapace and the secondabdominal segment with much projected tooth like structure in earlier specimen while in the latter the spot stretches over two posterior dorsal teeth of the carapace and without prominent projection in the second abdominal segment. The petasma structure of S. parajaponica is different from related species, with the presence of distal ventrolateral lobes stretched transversely while it is subcircular in S. japonica . Rear part of thelycum considerably enlarged in S. parajaponica than S. japonica

The gene sequence obtained from the present specimen was deposited in GenBank (Accession Number: MN816389 , MN816390 ) showed a sequence length of 610 and 600 bp for cytochrome c oxidase I (COI) gene. The present specimen sequences were compared with the NCBI sequences of the genus Sicyonia obtained from the GenBank ( Table. 1 ). The level of intraspecies genetic divergence within the Indian material was 0% with COI while interspecies genetic divergence varied from 19% ( S.picta ) to 29.4% ( S.pencillata ) between the present specimen and 11 species of Sicyonia sequences collected from NCBI was depicted in Fig.2 . COI sequence divergences of less than 3% are generally considered to be intraspecific in decapod crustaceans ( Darling 2011; Vergamini et al. 2011; Yang et al. 2016).

Figures

FIGURE 1. Sicyonia parajaponica Crosnier, 2003, A: Male total view. B: Female total view. C: Lateral view of rostrum bidentate tip (Bt) and hepatic spine (Hs). D. Carapace with posterior teeth large and strong. E. Tooth of the 1st and 2nd abdominal somite with strong and acute. Fourth abdominal postero-ventral margin with 3 spines. G. Distal ventrolateral lobes of petasma. H. Enlarged thelycum

FIGURE 2. Phylogenetic tree of the genera Sicyonia using Maximum Likelihood with 1000 bootstrap under the best fitting model GTR+G+I inferred from DNA sequences of COI mitochondrial gene.